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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting situations where an NxStage System One HD machine triggers air detector alarms or abnormal venous pressure readings. These alarms typically indicate external causes such as tubing kinks, disconnections, or sensor blockages. Internal sensor failure is less common but possible. The focus is on simple, safe, external checks before escalating for repair.
Step-by-Step Troubleshooting
Ensure Patient Safety
- Stop dialysis and move the patient to another machine if needed.
- Do not troubleshoot the line while blood is circulating in the patient.
Inspect Tubing and Connections
- Check arterial and venous lines for kinks, clots, or air bubbles.
- Ensure all luer locks and connections are fully seated.
- Proper flow without obstruction prevents false alarms.
Check for Air in the Circuit
- Inspect the blood circuit for air bubbles.
- If air is present, follow the machine’s standard air removal protocol.
- Air in the line can trigger both air detector and pressure alarms.
Inspect the Pressure Transducers
- Ensure transducer connectors are properly seated on the machine.
- Look for bent, loose, or damaged pins.
- Confirm the transducer and tubing are dry and free of moisture.
Examine the Air Detector Chamber
- Confirm it is properly installed and seated.
- Ensure no cracks, fluid contamination, or obstructions are present.
Swap Components if Needed
- If alarms persist, swap the blood circuit or sensor module with a known good one.
- This confirms whether the issue is consumable or device-related.
Check Machine Settings
- Confirm arterial and venous pressure alarm thresholds are set appropriately for the patient and treatment.
If the Problem Persists
External and easily verifiable issues have been ruled out. The issue may be due to internal sensor failure or a board fault.
Next Steps:
- Remove the machine from service.
- Label it “Out of Service.”
- Send the machine to the service bench or authorized repair center.
Clinical Use Tip
- Always prioritize patient safety over troubleshooting.
- Move the patient to another dialysis machine first.
- Only manipulate tubing and sensors once the circuit is not connected to the patient.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Machine triggered air detector and venous pressure alarms during treatment.”
Cause
What was observed during troubleshooting.
Example:
“Arterial line was kinked; air detector chamber properly seated but clogged with residual fluid.”
Resolution
What action was taken.
Example:
“Removed kink in tubing; replaced air detector chamber; tested machine with a dummy circuit. Alarms cleared and machine returned to service.”
Helpful Details to Include
- Check outlet and power supply
- Verify all connectors and sensors are dry and seated
- Note unusual sounds, fluid in the detector chamber, or abnormal pressures
- Record final device status after troubleshooting
Final Thought
Patient safety is paramount. Following a logical, stepwise troubleshooting approach ensures external causes are addressed first, minimizing unnecessary downtime or risk. Proper documentation using the CCR method provides accountability and clarity for any future service needs.
That is successful troubleshooting.